The invention pertains to gyratory crushers for reducing material to desired sizes. More particularly, the invention pertains to a gyratory cone type crusher in which the crushing head is carried on a shaft which is rotatably driven by an eccentric so that the head is gyrated upon rotation of the eccentric. A problem which is frequently encountered in gyratory crushers is the fact that the cone crusher head in running idle or no load condition tends to rotate with the eccentric. The cause of the spinning is the frictional drag that occurs between the crusher head shaft and the eccentric drive mechanism. If the spinning is excessive, it can damage the contact oil seals and bearings. Also, when material is fed into the crusher in which the crusher head is spinning, excessive wear of the crushing surfaces can occur due to skidding between the surfaces and the material. To prevent such crusher head spinning many approaches have been taken with varying degrees of success.
Examples of crushers in which antispin devices are incorporated are shown in U.S. Pat. Nos. 1,960,980; 3,207,449; 3,473,743; 3,539,119 and 3,743,193.
However, in a crusher where the crusher head shaft is adjustable, the anchor point of the antispin device can be fixed to the stationary frame. In this arrangement, provision must be made to allow the antispin device to work for all possible crusher shaft positions. When the crusher is idling the crusher head shaft tends to spin in the same direction as the drive eccentric rotates. When the crusher is working the crusher head shaft rotates slowly in the opposite direction with respect to the direction in which the drive eccentric is rotating. Thus, an antispin device must allow for this reverse rotation.